Cisco 400-007 Exam With Confidence Using Practice Dumps

D (Queue thresholding on the host subinterface):Protects CPU resources by limiting the amount of control plane traffic destined to the router itself.

E (Port filtering on the host subinterface):Allows fine-grained filtering of control plane traffic based on specific protocols or ports, protecting sensitive processes like routing protocols or management access.

Other options explained:

A, B, C: Transit subinterfaces protect forwarding plane transit traffic, not traffic destined to the control plane.

When unmanaged switches are connected to access ports, there ' s a risk that they may start participating in Spanning Tree Protocol (STP) or introduce loops. BPDU Guard is the most effective mechanism to mitigate this risk:

BPDU Guard disables a port immediately upon receiving any BPDU, ensuring that only end hosts (non-switch devices) are connected to access ports.

This protects the stability of the STP topology by preventing accidental or malicious introduction of switches into the Layer 2 domain.

Other options explained:

A (PortFast): Accelerates port transition to forwarding state but does not protect against loops caused by BPDUs.

B (UDLD): Detects unidirectional physical link failures but not STP participation.

C (Root guard): Prevents the connected device from becoming a root bridge but still allows BPDUs.

—